Neuroblastoma (NB) is a neural crest-derived malignancy that accounts for approximately 15% of pediatric cancer deaths. Importantly, NB arises from a failure of sympathoadrenal progenitors to differentiate. Furthermore, the degree of tumor differentiation strongly correlates with NB outcome, as the most undifferentiated tumors are predictive of poor overall survival. We have recently identified a novel pathway that is capable of restricting NB differentiation, and this pathway involves de-regulation of the histone chaperone CHAF1A (chromatin assembling factor-1A). CHAF1A is a major epigenetic and transcriptional regulator and its aberrant expression has recently been linked to tumorigenesis in numerous cancers. We found that high CHAF1A expression strongly predicts poor NB survival and an undifferentiated phenotype. Importantly, we show that CHAF1A is necessary for in vivo tumor establishment and growth, restricts NB differentiation, and rewires distinct metabolic programs. Thus, our guiding hypothesis is that NB remains frozen in a highly undifferentiated state in part due to CHAF1A-mediated suppression of differentiation programs and metabolic reprogramming. Our working model is that by blocking CHAF1A functions, we can drive NB to differentiate. The specific aims of this proposal will test these hypotheses and determine: 1) the contribution of CHAF1A to NB resistance to differentiation therapy, 2) the molecular mechanisms through which CHAF1A blocks NB differentiation and reprograms tumor metabolism, and 3) how CHAF1A metabolic reprogramming alters NB tumorigenesis and response to differentiation therapy. We expect to uncover the molecular mechanisms by which CHAF1A opposes NB differentiation and to identify genes and pathways that alter tumor metabolism in CHAF1A-driven tumorigenesis. We expect that the proposed research will also more generally provide new insight into the transcriptional regulation of NB differentiation and energy metabolism in NB progression and resistance to therapy. These studies will be significant as these findings will lead to develop novel differentiation therapies for NB.